Journey to the Moon: Engineer Reveals the Most Exciting Moment in the NTV Interview

It is probably mankind’s greatest adventure: a journey to the moon. With the “Artemis” program, NASA wants to return to the Earth’s satellite. In the year 2025, but possibly not until 2026, a human will set foot on the moon again. dThe European Space Agency ESA helped develop and build the lunar spacecraft “Orion”. Now the dress rehearsal is just around the corner: a test flight with the “Artemis 1” mission is expected to start on November 16 without astronauts to the moon. All systems must then be “put to the test”, as German ESA engineer Dr. Tobias Langener explained in an interview with He is responsible for the propulsion system of the spaceship. Mr. Langener, how does it feel to be involved in humanity’s new moon program?

Tobias Langener: It’s a bit surreal. I usually don’t have much time to think about it because we have a very demanding and stressful development program. Every day there are problems that need to be solved. But when I look at it from a distance, I do think: wow, you’re participating in the largest space program in the world. It is of course also a great responsibility, but at the same time very exciting.

They are on site at NASA’s Houston Control Center when “Artemis 1” is launched. Are you sitting there in the great room with the huge screens on the wall that you know from television?

This is the room where the flight controllers are. Beyond that, though, is another room that looks almost exactly like where we sit, the engineers who were involved in designing and building the spacecraft. It is the so-called Mission Evaluation Room. There is constant communication between the two rooms. For example, if a problem arises, the flight controllers call the Mission Evaluation Room. For example, if a valve in the spaceship’s propulsion system won’t open, we’ll have to come up with a solution to get it open.

How is the mood in the Mission Evaluation Room? It’s about a lot.

ESA engineer Tobias Langener in front of a model of the “Orion” spacecraft.

(Photo: ESA/T. Langener)

You really feel the tension there. You have to imagine that the whole boot process starts 46 hours before the countdown reaches zero. The spaceship is turned on, the systems are then powered up and the voltage slowly builds up. I’ll be at the control center about five hours before launch. When I leave the hotel, I can already see on TV that the rocket is being refueled. In the Mission Evaluation Room the atmosphere is very calm but tense. You notice that everyone is concentrated in front of the screens. This is of course very exciting.

There have already been several aborted starts with “Artemis 1”. Is it because the moon rocket isn’t working properly yet?

Aborting the start is completely normal. There were shuttle flights where the takeoff was aborted four times and the crew had to climb out again and again. But at least it’s good. On “Apollo 1” in the early 1960s, the crew was already inside the capsule when it suddenly caught fire. The astronauts died in the process. And because of such incidents, you approach it very carefully. After all, such a system consists of tens of thousands of components. The chance that one of them will cause problems is relatively high. However, during the first two attempts to launch “Artemis 1”, there were problems with the rocket, but not with the spaceship. With that everything looked very good and we were “ready to launch”.

It is also a first flight for the rocket, called the Space Launch System or SLS for short. Worried something could go wrong at launch?


The lunar spaceship “Orion” consists of the crew module and the supply module ESM.

(Photo: dpa)

I don’t worry much. Of course, it’s a new rocket and there are always risks. However, the engines were previously used on the Space Shuttle. The entire main stage was also fully tested beforehand. The solid fuel engines are also relatively robust. There have been few problems so far except for the “Challenger” accident…

…the explosion of a space shuttle shortly after launch in 1986.

In fact, the SLS uses the same boosters. But lessons have been learned from the “Challenger” disaster and since then there have been no more problems with these solid fuel engines. The top stage of the rocket has also been well tested, so I’m relatively relaxed.

Is there a moment at the beginning of “Artemis 1” that you particularly look forward to?

Ultimately it is the ignition of the rocket. If it works, we’ll fly. Once the solid fuel engines are on, they burn for about two minutes and after that you can’t turn anything off. It is the point of no return.

The European Service Module ESM, built by Airbus in Bremen, will provide the lunar spacecraft’s propulsion, electricity, water and oxygen supply. As chief engineer you are responsible for the propulsion system – what should you pay particular attention to when starting?

The moment I especially look forward to is called priming. The ESM’s propulsion system is put into the status so that it can then perform all necessary maneuvers. Priming takes place two minutes and ten seconds after launch and lasts approximately two minutes. If that all works out, I’ll be relieved. This is one of the greatest moments of ascension. The first ignition of our main engine about five hours after takeoff is also very exciting. This engine was also used in the shuttle.

The propulsion of the spaceship should also be able to save lives in later manned missions…

Yes, exactly. If there is a problem with the rocket after launch, the ESM’s propulsion system is responsible for flying the “Orion” spacecraft away from a certain height of the rocket. It then takes the capsule around the Earth with the astronauts so that they can land safely again in the Pacific Ocean. Or it puts them in orbit from where they can land safely again. It all depends on the level at which you cancel.

Is the propulsion system you oversee also responsible for getting the spacecraft to the moon?

Generally yes. The propulsion system also allows you to fly to the moon. When this feature is needed depends on the mission. At “Artemis 1” the shot to the moon is made by the upper stage of the SLS rocket, at “Artemis 2” then by the propulsion system of the starship. All the maneuvers needed to return to Earth are also provided by the spacecraft’s propulsion system.

Why is the spaceship propulsion used differently in the “Artemis 2” mission than in “Artemis 1”?

Astronauts fly “Artemis 2” for the first time. After the spacecraft is detached from the SLS rocket, it will initially remain in orbit for a day to test vital systems and maneuvers near Earth. The “Orion” propulsion system then transports the capsule in the direction of the moon, which is then only flown past, i.e. not in orbit around the moon, but directly back to Earth. You want to keep this mission short, about nine to 10 days, to minimize the risk to the astronauts. .

What about the later missions?

In “Artemis 3” and “Artemis 4” the rocket makes the bullet to the moon again, since the fuel of the “Orion” spaceship is needed more around the moon and for the return. Astronauts are flying these missions again, and the first moon landings since 1972 are planned. Incidentally, the lunar module is being built by SpaceX.

To what extent is “Orion” actually similar to those spaceships used in the earlier moon flights of the “Apollo” program?

The “Orion” capsule is certainly much bigger, you can take four astronauts with you and thus one more than with “Apollo”. And you have more space inside. I got to sit in an “Orion” model in Houston. It still felt very small to me personally, but it’s comfortable for a spaceship. The spaceship “Orion” also has more engines and solar cells on board. In “Apollo” the electricity was generated with fuel cells. And compared to “Apollo”, “Orion” is much more advanced in terms of computer technology. There is a very complex software that can relieve the astronauts of many tasks. “Orion” is also designed for longer missions.

Now technically aside, why do you think it’s important to fly to the moon?

Firstly, it is a very important contribution for Europe. Because “Artemis” is a huge space mission, similar to “Apollo” back then, but the European space industry today is very powerful and can participate in such a large and demanding program. This also opens up the possibility that European astronauts will be allowed to fly to the gateway…

… the planned station in orbit around the moon. In later missions, astronauts from the “Orion” spacecraft must transfer to a landing module to land on the moon from there.

And the search for the moon resumes. There are also ideas to use the moon economically, which is important to justify the huge investments. On the other hand, the point is also that the moon could be a stepping stone to later fly to Mars from there. “Artemis” will also be important to inspire younger generations. “Apollo” had also inspired many and may have contributed to people interacting with technologies later in school and college.

You mentioned Mars – would you dream of working on a spaceship someday?

I previously worked on ExoMars, the European rover mission that is now being redefined after the discontinued cooperation with Russia. Taking humans to Mars is, of course, a whole other level. But if it came to that, it would be a big challenge for me to contribute in any way.

Kai Stoppel spoke with Tobias Langener

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